package d1_regex;

public class RegexTest {
    public static void main(String[] args) {

    }

    public static boolean QQcheck(String qq) {
        if (qq == null || qq.startsWith("0") || qq.length() < 6 || qq.length() > 20) {
            return false;
        }

        for (int i = 0; i < qq.length(); i++) {
            char ch = qq.charAt(i);
            if (ch < '0' || ch > '9') {
                return false;
            }
        }
        return true;
    }

}
